Silicon effects on the wet oxidation of type 310 stainless steel

The wet oxidation performance of a high-Si (5.9 wt.%) Type 310 stainless steel exposed in flowing ambient pressure (0.1 MPa) air-10% H2O mixture at 800 °C was investigated. A lower parabolic rate constant, relative to that exhibited by conventional low-Si (0.6 wt.%) Type 310S stainless steel, in the observed paralinear kinetics is linked to the formation of a continuous SiO2 layer at the oxide scale/metal interface. Accelerated formation of non-protective Fe-rich oxides is significantly delayed due to Cr-rich silicide intermetallic phase, present in the starting microstructure, serving as reservoir to sufficiently supply Cr to replace oxidized Cr lost to volatilization.